Contents
Images
Upload your image
DSS Images Other Images
Related articles
Molecular gas in the galaxy cluster Abell 262. CO observations of UGC 1347 and other galaxies of the cluster
We present millimeter CO line emission observations of 12 galaxieswithin the Abell 262 cluster, together with L_FIRdata, in the context of a possible molecular gas deficiency within theregion of the cluster center. Several indications of the presence ofsuch a deficiency are highlighted and connected to a model ofcirrus-like cloud stripping. The model predicts a drop in the average100 μm flux density of galaxies in the core of the cluster comparedto the average 100 μm flux density in the outer regions, which isactually indicated in the IRAS data of the cluster members. This drop isexplained by the decrease in the total hydrogen column density N(H) and,therefore, also includes a decrease in the molecular gas content. Inaddition to results for the global CO content of the galaxy sample,high-resolution interferometric CO(1-0) observations of one of thecluster members, UGC 1347, exemplify the spatial distribution of themolecular gas in a galaxy of the cluster. With these observations, itwas possible to confirm the existence of a bright off-nuclearCO-emission source and to derive molecular masses and line ratios forthis source and the nucleus.
| M/L, Hα Rotation Curves, and H I Measurements for 329 Nearby Cluster and Field Spirals. I. Data
A survey of 329 nearby galaxies (redshift z<0.045) has been conductedto study the distribution of mass and light within spiral galaxies overa range of environments. The 18 observed clusters and groups span arange of richness, density, and X-ray temperature and are supplementedby a set of 30 isolated field galaxies. Optical spectroscopy taken withthe 200 inch (5 m) Hale Telescope provides separately resolved Hαand [N II] major-axis rotation curves for the complete set of galaxies,which are analyzed to yield velocity widths and profile shapes, extents,and gradients. H I line profiles provide an independent velocity widthmeasurement and a measure of H I gas mass and distribution. I-bandimages are used to deconvolve profiles into disk and bulge components,to determine global luminosities and ellipticities, and to checkmorphological classification. These data are combined to form a unifieddata set ideal for the study of the effects of environment upon galaxyevolution.
| The ISOPHOT 170 μm Serendipity Survey II. The catalog of optically identified galaxies%
The ISOPHOT Serendipity Sky Survey strip-scanning measurements covering≈15% of the far-infrared (FIR) sky at 170 μm were searched forcompact sources associated with optically identified galaxies. CompactSerendipity Survey sources with a high signal-to-noise ratio in at leasttwo ISOPHOT C200 detector pixels were selected that have a positionalassociation with a galaxy identification in the NED and/or Simbaddatabases and a galaxy counterpart visible on the Digitized Sky Surveyplates. A catalog with 170 μm fluxes for more than 1900 galaxies hasbeen established, 200 of which were measured several times. The faintest170 μm fluxes reach values just below 0.5 Jy, while the brightest,already somewhat extended galaxies have fluxes up to ≈600 Jy. For thevast majority of listed galaxies, the 170 μm fluxes were measured forthe first time. While most of the galaxies are spirals, about 70 of thesources are classified as ellipticals or lenticulars. This is the onlycurrently available large-scale galaxy catalog containing a sufficientnumber of sources with 170 μm fluxes to allow further statisticalstudies of various FIR properties.Based on observations with ISO, an ESA project with instruments fundedby ESA Member States (especially the PI countries: France, Germany, TheNetherlands and the UK) and with the participation of ISAS and NASA.Members of the Consortium on the ISOPHOT Serendipity Survey (CISS) areMPIA Heidelberg, ESA ISO SOC Villafranca, AIP Potsdam, IPAC Pasadena,Imperial College London.Full Table 4 and Table 6 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/422/39
| Dark halo properties from rotation curves
We study a large set of high spatial resolution optical rotation curvesof galaxies with the goal of determining the model parameters for a discembedded within a cold dark matter (CDM) halo, which we model witheither a Navarro-Frenk-White (NFW) profile or pseudo-isothermal profile.We show that parameter degeneracies present in lower resolution data arelifted at these higher resolutions. 34 per cent of the galaxies do nothave a meaningful fit when using the NFW profile and 32 per cent whenusing the pseudo-isothermal profile, however only 14 per cent do nothave a meaningful fit in either model. In both models we findcorrelations between the disc baryon fraction fd and the spinparameter of the halo λ', between fd and the dark halomass M200, and between M200 and the concentrationparameter c. We show that the distribution of the concentrationparameter c, for a NFW halo, is in good agreement with CDM predictions;no significant galaxy population is found with very low values of c. Theoverall distribution of λ' is in good agreement with theoreticalpredictions from hierarchical tidal torque theory. The whole sample isalso well fitted by a pseudo-isothermal dark halo with a core, but thesize of the core is rather small (6 per cent of the virial radius orsmaller; for 70 per cent of the sample the core size is less than 2kpc). Thus we conclude that the profile of dark matter is steep(r-1 or steeper) down to this radius; large dark matter cores(and therefore very low dark matter central densities) seem to beexcluded. Low-surface-brightness galaxies tend to have higher values ofλ' for a given fd and lower values of c for a givenmass than high-surface-brightness galaxies. In an appendix we give someuseful formulae for pseudo-isothermal profile haloes and we discuss indetail the issue of parameter degeneracies.
| The calibration of the extragalactic distance scale: methods and problems.
Not Available
| Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, whichis a complete, distance-limited (cz<=6000 km s-1) andmagnitude-limited (B<=14) sample of ~7000 optical galaxies. Thesample covers 2/3 (8.27 sr) of the sky (|b|>20deg) andappears to have a good completeness in redshift (97%). We select thesample on the basis of homogenized corrected total blue magnitudes inorder to minimize systematic effects in galaxy sampling. We identify thegroups in this sample by means of both the hierarchical and thepercolation ``friends-of-friends'' methods. The resulting catalogs ofloose groups appear to be similar and are among the largest catalogs ofgroups currently available. Most of the NOG galaxies (~60%) are found tobe members of galaxy pairs (~580 pairs for a total of ~15% of objects)or groups with at least three members (~500 groups for a total of ~45%of objects). About 40% of galaxies are left ungrouped (field galaxies).We illustrate the main features of the NOG galaxy distribution. Comparedto previous optical and IRAS galaxy samples, the NOG provides a densersampling of the galaxy distribution in the nearby universe. Given itslarge sky coverage, the identification of groups, and its high-densitysampling, the NOG is suited to the analysis of the galaxy density fieldof the nearby universe, especially on small scales.
| The Correlation between Galaxy H I Line Widths and K'Luminosities
The relationship between galaxy luminosities and rotation rates isstudied with total luminosities in the K' band. Extinction problems areessentially eliminated at this band centered at 2.1 μm. A templateluminosity-line width relation is derived based on 65 galaxies drawnfrom two magnitude-limited cluster samples. The zero point is determinedusing four galaxies with accurately known distances. The calibration isapplied to give the distance to the Pisces Cluster (59 Mpc) at aredshift in the cosmic microwave background frame of 4771 kms-1. The resultant value of the Hubble constant is 81 kms-1Mpc-1. The largest sources of uncertainty arethe small number of zero-point calibrators at this time at K' and thepresent application to only one cluster.
| Distances to Galaxies from the Correlation between Luminosities and Line Widths. III. Cluster Template and Global Measurement of H0
The correlation between the luminosities and rotation velocities ofgalaxies can be used to estimate distances to late-type galaxies. It isan appropriate moment to reevaluate this method given the great deal ofnew information available. The major improvements described hereinclude: (1) the template relations can now be defined by large,complete samples, (2) the samples are drawn from a wide range ofenvironments, (3) the relations are defined by photometric informationat the B, R, I, and K' bands, (4) the multiband information clarifiesproblems associated with internal reddening, (5) the template zeropoints are defined by 24 galaxies with accurately known distances, and(6) the relations are applied to 12 clusters scattered across the skyand out to velocities of 8000 km s-1. The biggest change fromearlier calibrations are associated with point 5. Roughly a 15% increasein the distance scale has come about with the fivefold increase in thenumber of zero-point calibrators. The overall increase in the distancescale from the luminosity-line width methodology is about 10% afterconsideration of all factors. Modulo an assumed distance to the LargeMagellanic Cloud of 50 kpc and no metallicity corrections to the Cepheidcalibration, the resulting value of the Hubble constant isH0=77+/-8 km s-1 Mpc-1, where the erroris the 95% probable statistical error. Cumulative systematic errorsinternal to this analysis should not exceed 10%. Uncertainties in thedistance scale ladder external to this analysis are estimated at ~10%.If the Cepheid calibration is shifted from the LMC to NGC 4258 with adistance established by observations of circumnuclear masers, thenH0 is larger by 12%.
| Box- and peanut-shaped bulges. I. Statistics
We present a classification for bulges of a complete sample of ~ 1350edge-on disk galaxies derived from the RC3 (Third Reference Catalogue ofBright Galaxies, de Vaucouleurs et al. \cite{rc3}). A visualclassification of the bulges using the Digitized Sky Survey (DSS) inthree types of b/p bulges or as an elliptical type is presented andsupported by CCD images. NIR observations reveal that dust extinctiondoes almost not influence the shape of bulges. There is no substantialdifference between the shape of bulges in the optical and in the NIR.Our analysis reveals that 45% of all bulges are box- and peanut-shaped(b/p). The frequency of b/p bulges for all morphological types from S0to Sd is > 40%. In particular, this is for the first time that such alarge frequency of b/p bulges is reported for galaxies as late as Sd.The fraction of the observed b/p bulges is large enough to explain theb/p bulges by bars. Partly based on observations collected at ESO/LaSilla (Chile), DSAZ/Calar Alto (Spain), and Lowell Observatory/Flagstaff(AZ/U.S.A.). Tables 6 and 7 are only available in electronic form at CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| The I-Band Tully-Fisher Relation for SC Galaxies: 21 Centimeter H I Line Data
A compilation of 21 cm line spectral parameters specifically designedfor application of the Tully-Fisher (TF) distance method is presentedfor 1201 spiral galaxies, primarily field Sc galaxies, for which opticalI-band photometric imaging is also available. New H I line spectra havebeen obtained for 881 galaxies. For an additional 320 galaxies, spectraavailable in a digital archive have been reexamined to allow applicationof a single algorithm for the derivation of the TF velocity widthparameter. A velocity width algorithm is used that provides a robustmeasurement of rotational velocity and permits an estimate of the erroron that width taking into account the effects of instrumental broadeningand signal-to-noise. The digital data are used to establish regressionrelations between measurements of velocity widths using other commonprescriptions so that comparable widths can be derived throughconversion of values published in the literature. The uniform H I linewidths presented here provide the rotational velocity measurement to beused in deriving peculiar velocities via the TF method.
| The I-Band Tully-Fisher Relation for SC Galaxies: Optical Imaging Data
Properties derived from the analysis of photometric I-band imagingobservations are presented for 1727 inclined spiral galaxies, mostly oftypes Sbc and Sc. The reduction, parameter extraction, and errorestimation procedures are discussed in detail. The asymptotic behaviorof the magnitude curve of growth and the radial variation in ellipticityand position angle are used in combination with the linearity of thesurface brightness falloff to fit the disk portion of the profile. TotalI-band magnitudes are calculated by extrapolating the detected surfacebrightness profile to a radius of eight disk scale lengths. Errors inthe magnitudes, typically ~0.04 mag, are dominated by uncertainties inthe sky subtraction and disk-fitting procedures. Comparison is made withthe similar imaging database of Mathewson, Ford, & Buchhorn, both aspresented originally by those authors and after reanalyzing theirdigital reduction files using identical disk-fitting procedures. Directcomparison is made of profile details for 292 galaxies observed incommon. Although some differences occur, good agreement is found,proving that the two data sets can be used in combination with onlyminor accommodation of those differences. The compilation of opticalproperties presented here is optimized for use in applications of theTully-Fisher relation as a secondary distance indicator in studies ofthe local peculiar velocity field.
| Near-infrared observations of galaxies in Pisces-Perseus. I. vec H-band surface photometry of 174 spiral
We present near-infrared, H-band (1.65 $() μm), surface photometry of174 spiral galaxies in the area of the Pisces-Perseus supercluster. Theimages, acquired with the ARNICA camera mounted on various telescopes,are used to derive radial profiles of surface brightness, ellipticities,and position angles, together with global parameters such as H-bandmagnitudes and diameters Radial profiles in tabular form and images FITSfiles are also available upon request from gmorio@arcetri.astro.it.}.The mean relation between H-band isophotal diameter D_{21.5} and theB-band D25 implies a B-H color of the outer disk bluer than3.5; moreover, D_{21.5}/D25 depends on (global) color andabsolute luminosity. The correlations among the various photometricparameters suggest a ratio between isophotal radius D_{21.5}/2 and diskscale length of ~ m3.5 and a mean disk central brightness ~ meq 17.5H-mag arcsec^{-2}. We confirm the trend of the concentration indexC31$ with absolute luminosity and, to a lesser degree, withmorphological type. We also assess the influence of non-axisymmetricstructures on the radial profiles and on the derived parameters. Basedon observations at the TIRGO, NOT, and VATT telescopes. TIRGO(Gornergrat, CH) is operated by CAISMI-CNR, Arcetri, Firenze. NOT (LaPalma, Canary Islands) is operated by NOTSA, the Nordic ObservatoryScientific Association. VATT (Mt. Graham, Az) is operated by VORG, theVatican Observatory Research Group Table 3 and Fig. 4 are only availablein electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html.
| Near-infrared observations of galaxies in Pisces-Perseus. III. Global scaling relations of disks and bulges
We determine the parameters of scaling relations analogous to theFundamental Plane of elliptical galaxies for the bulges and disks of asample of 40 spiral galaxies. To this end we derive structuralparameters (scalelengths and surface brightnesses) from near infrared Hband images, and kinematical parameters (rotational velocities) fromoptical rotation curves. In the case of the disks, we test the accuracyof the derived relation as a distance indicator by comparing its scatterto that of the H band Tully-Fisher relation for the same sample, andfind that the accuracy attained by the latter is slightly higher (thedispersion is 19% versus 23% for this sample). It is speculated that thedifference is due to the more robust character of global parameters,rather than those associated with the inner parts of disks. It alsoapperas that (a) either the stellar mass-to-light ratios of bulge anddisk increase with the size of the components, or (b) the bulge and diskrelative contributions to the overall rotation of the galaxy (and, as aconsequence, to its total mass) become steadily smaller with increasingsize.
| Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies
We present a catalogue of aperture photometry of galaxies, in UBVRI,assembled from three different origins: (i) an update of the catalogueof Buta et al. (1995) (ii) published photometric profiles and (iii)aperture photometry performed on CCD images. We explored different setsof growth curves to fit these data: (i) The Sersic law, (ii) The net ofgrowth curves used for the preparation of the RC3 and (iii) A linearinterpolation between the de Vaucouleurs (r(1/4) ) and exponential laws.Finally we adopted the latter solution. Fitting these growth curves, wederive (1) the total magnitude, (2) the effective radius, (3) the colourindices and (4) gradients and (5) the photometric type of 5169 galaxies.The photometric type is defined to statistically match the revisedmorphologic type and parametrizes the shape of the growth curve. It iscoded from -9, for very concentrated galaxies, to +10, for diffusegalaxies. Based in part on observations collected at the Haute-ProvenceObservatory.
| Homogeneous Velocity-Distance Data for Peculiar Velocity Analysis. III. The Mark III Catalog of Galaxy Peculiar Velocities
This is the third in a series of papers in which we assemble and analyzea homogeneous catalog of peculiar velocity data. In Papers I and II, wedescribed the Tully-Fisher (TF) redshift-distance samples thatconstitute the bulk of the catalog and our methodology for obtainingmutually consistent TF calibrations for these samples. In this paper, wesupply further technical details of the treatment of the data andpresent a subset of the catalog in tabular form. The full catalog, knownas the Mark III Catalog of Galaxy Peculiar Velocities, is available inaccessible on-line databases, as described herein. The electroniccatalog incorporates not only the TF samples discussed in Papers I andII but also elliptical galaxy Dn- sigma samples originally presentedelsewhere. The relative zero pointing of the elliptical and spiral datasets is discussed here. The basic elements of the Mark III Catalog arethe observables for each object (redshift, magnitude, velocity width,etc.) and inferred distances derived from the TF or Dn- sigma relations.Distances obtained from both the forward and inverse TF relations aretabulated for the spirals. Malmquist bias--corrected distances arecomputed for each catalog object using density fields obtained from theIRAS 1.2 Jy redshift survey. Distances for both individual objects andgroups are provided. A variety of auxiliary data, including distancesand local densities predicted from the IRAS redshift surveyreconstruction method, are tabulated as well. We study the distributionsof TF residuals for three of our samples and conclude that they are wellapproximated as Gaussian. However, for the Mathewson et al. sample wedemonstrate a significant decrease in TF scatter with increasingvelocity width. We test for, but find no evidence of, a correlationbetween TF residuals and galaxy morphology. Finally, we derivetransformations that map the apparent magnitude and velocity width datafor each spiral sample onto a common system. This permits theapplication of analysis methods that assume that a unique TF relationdescribes the entire sample.
| Optical Rotation Curves and Linewidths for Tully-Fisher Applications
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.2402C&db_key=AST
| The I band Tully-Fisher relation for cluster galaxies: data presentation.
Observational parameters which can be used for redshift-independentdistance determination using the Tully-Fisher (TF) technique are givenfor \ntot spiral galaxies in the fields of 24 clusters or groups. I bandphotometry for the full sample was either obtained by us or compiledfrom published literature. Rotational velocities are derived either from21 cm spectra or optical emission line long-slit spectra, and convertedto a homogeneous scale. In addition to presenting the data, a discussionof the various sources of error on TF parameters is introduced, and thecriteria for the assignment of membership to each cluster are given.
| Deep r-Band Photometry for Northern Spiral Galaxies
We present r-band surface photometry for 349 northern Sb-Sc UGCgalaxies, from a total of 627 CCD images. For each galaxy, we presentsurface brightness profiles, isophotal and total magnitudes, isophotalradii, and structural parameters from exponential fits to the disk. Onehundred ninety-five galaxies have been observed more than once. Allnights with a photometric transformation scatter greater than 0.022 magwere rejected. Sky errors are investigated carefully and yield profilesthat are reliable down to 26 r mag arcsec^-2^, Deep isophotal magnitudesare as accurate as +/-0.019, and extrapolated magnitudes are internallyconsistent to within 0.020. We compare visual (UGC) and CCD isophotaldiameters and show that axial ratio must be included as a thirdparameter. Comparison with the r-band CCD photometry of Kent andWillick, and accounting for sky errors, suggest typical errors for totalmagnitudes of +/-0.08. Our data are also shown to be zero-pointed on thesame Gunn r system as that of Kent and Willick. Ellipticity measurementsagree very well except for progressively face-on galaxies where spiralstructure is more conspicuous. The ellipticity internal error is lessthan 0.02, or about 3^deg^ for inclinations. Our internal extinctioncorrection implies that disks are semitransparent in their outer parts.We caution that comparison of central surface brightnesses and scalelengths is complicated by the subjective nature of their measurement;extreme care must be applied when using such quantities. We measure anapparent Freeman law of (μ_0,c_) = 20.08 +/- 0.55 r mag arcsec^-2^.This magnitude-limited sample was originally derived for studies oflarge-scale motions in the local universe. The deep CCD photometry isalso ideally suited for matching spectroscopic studies, mass modeling,galaxy structural analysis, etc.
| An image database. II. Catalogue between δ=-30deg and δ=70deg.
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
| Recalibration of the H-0.5 magnitudes of spiral galaxies
The H-magnitude aperture data published by the Aaronson et al.collaboration over a 10 year period is collected into a homogeneous dataset of 1731 observations of 665 galaxies. Ninety-six percent of thesegalaxies have isophotal diameters and axial ratios determined by theThird Reference Cataloque of Bright Galaxies (RC3; de Vaucouleurs et al.1991), the most self-consistent set of optical data currently available.The precepts governing the optical data in the RC3 are systematicallydifferent from those of the Second Reference Catalogue (de Vaucouleurs,de Vaucouleurs, & Corwin 1976), which were used by Aaronson et al.for their original analyses of galaxy peculiar motions. This in turnleads to systematic differences in growth curves and fiducialH-magnitudes, prompting the present recalibration of the near-infraredTully-Fisher relationship. New optically normalized H-magnitude growthcurves are defined for galaxies of types SO to Im, from which new valuesof fiducial H-magnitudes, Hg-0.5, are measured forthe 665 galaxies. A series of internal tests show that these fourstandard growth curves are defined to an accuracy of 0.05 mag over theinterval -1.5 less than or equal to log (A/Dg) less than orequal to -0.2. Comparisons with the Aaronson et al. values of diameters,axial ratios, and fiducial H-magnitudes show the expected differences,given the different definitions of these parameters. The values ofHg-0.5 are assigned quality indices: a qualityvalue of 1 indicates an accuracy of less than 0.2 mag, quality 2indicates an accuracy of 0.2-0.35 mag, and quality 3 indicates anaccuracy of more than 0.35 mag. Revised values of corrected H I velocitywidths are also given, based on the new set of axial ratios defiend bythe RC3.
| General study of group membership. II - Determination of nearby groups
We present a whole sky catalog of nearby groups of galaxies taken fromthe Lyon-Meudon Extragalactic Database. From the 78,000 objects in thedatabase, we extracted a sample of 6392 galaxies, complete up to thelimiting apparent magnitude B0 = 14.0. Moreover, in order to considersolely the galaxies of the local universe, all the selected galaxieshave a known recession velocity smaller than 5500 km/s. Two methods wereused in group construction: a Huchra-Geller (1982) derived percolationmethod and a Tully (1980) derived hierarchical method. Each method gaveus one catalog. These were then compared and synthesized to obtain asingle catalog containing the most reliable groups. There are 485 groupsof a least three members in the final catalog.
| Peculiar motions in superclusters: Perseus--Pisces
We discuss the near infrared observations obtained for a set of 81galaxies in the region of the Perseus--Pisces supercluster. From these,in conjunction with the 21 cm data of the Arecibo sample, we estimatethe peculiar velocities via the Tully-Fisher relation and the model ofthe local perturbations as derived by Han and Mould. From the datadiscussed we find that the supercluster main structure is shrinking. Toexplain the size and velocities observed the model requires, for thesupercluster, a mean overdensity of about delta rho/rho = 9 whichcorresponds to a total mass of 1016 solar masses to cover anextension of about 100 Mpc.
| I-band CCD surface photometry of spiral galaxies in 16 nearby clusters
Results of I-band CCD surface photometry for 284 spiral galaxies in 16clusters in the redshift range from 3000 to 11,000 km/s are presented.Various effects on surface photometry are discussed, and the relevantcorrections are outlined.
| Axial ratios of edge-on spirals
A diameter-limited sample of 888 normal Sa-Sc galaxies was compiled fromthe Uppsala General Catalog. New micrometer measures of the axial ratiosR of the disk components of 262 edge-on spirals in this sample were madeon copies of blue Palomar Sky Survey plates and calibrated againstphotometric standards. The distribution of isophotal axial ratios forthe whole sample was analyzed to give information on the true axialratios R0 of spiral disks. The mean value of logR0 is 0.95 +/- 0.03 and the dispersion about this mean is0.12 +/- 0.04. A similar mean value (0.90) was obtained from avolume-limited sub-sample of 348 spirals. The dispersion in logR0 is partly due to a dependence of R0 onmorphological type, and the mean value of log R0 for eachtype was estimated. Inclinations of 342 edge-on (R is greater than about3) spirals were determined from their isophotal axial ratios and types.No significant dependence of R0 on luminosity at each typewas found.
| Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members
This paper gives a catalog of the groups and associations obtained bymeans of a revised hierarchical algorithm applied to a sample of 4143galaxies with diameters larger than 100 arcsec and redshifts smallerthan 6000 km/s. The 264 groups of galaxies obtained in this way (andwhich contain at least three sample galaxies) are listed, with the looseassociations surrounding them and the individual members of eachaggregate as well; moreover, the location of every entity among 13regions corresponding roughly to superclusters is specified. Finally,1729 galaxies belong to the groups, and 466 to the associations, i.e.,the total fraction of galaxies within the various aggregates amounts to53 percent.
| The Tully-Fisher relation in different environments
The Tully-Fisher relation (TFR) in different environments wasinvestigated in 13 galaxy samples spanning a large range in galaxydensities, using two statistical tests to compare the TFR of differentsamples. Results of the analysis of TFR parameters in severalenvironments showed that, when samples of similar data-accuracy andmagnitude-range were compared, there was no significant differencebetween the galaxy samples. It is suggested that a comparison of sampleswith very different data accuracy or those biased by incompletenesseffects may lead to misleading results.
| Periodicities in galaxy redshifts
Using new data for unassociated galaxies with wide H I profiles andvalues of period and solar motion predicted by Tifft and Cocke (1984), aperiodicity has been found which is significant at the conventional 5percent level. Together with Tifft's work on galaxy pairs and smallgroups, this result appears to provide evidence in favor of thehypothesis that measured galaxy redshifts occur in steps of a littlemore than 72 km/s or a simple multiple of this period.
| Determination of the relative spectrophotometric gradients of galaxies. IV
Relative spectrophotometric gradients of continua are determined for 195galaxies. The spectra have been obtained with the 70-cm meniscustelescope of the Abastumani Astrophysical Observatory using a 2-degpreobjective prism (the reverse linear dispersion was 1200 A/mm inH-gamma). The gradient values were reduced to the AO spectral class andcorrected for light absorption in the Galaxy.
| Sources of error in the Tully-Fisher relation - Reducing the scatter with CCD I-band surface photometry of spiral galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1987ApJ...313..629B&db_key=AST
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
Catalogs and designations:
|
